Circuit breaker



J. R. SANBORN CIRCUIT BREAKER June 5, 1934.

Filed Nov. 4, 1930 4 Sheets-Sheet l (D Smmwcoz June 5, 1934. J, R,SANBORN 1,961,573

C RCUIT BREAKER Filed Nov. 4, 1,930 4 sheets-sheet 2 June 5, 1934. J. R.sANBoRN 1,961,573

CIRCUIT BREAKER Filed Nov. 4, 1930 4 Sheets-Sheet 3 June 5, 1934. J. R.SANBORN CIRCUIT BREAKER 4 Sheets-Sheet 4 Filed Nov. 4. 1930 Patented.June 5, 1934 UNITED STATES CIRCUIT BREAKER John R. Sanborn, Bethlehem,Pa., assignor to Roller-Smith Company, a corporation of New YorkApplication November 4, 1930, Serial No. 493,297

14 Claims.

This invention relates particularly to the release from the handle typeof circuit breaker, or so-called nonclosable under an abnormal circuitcondition, such as overload, under-voltage, or any other desiredcontrolling factor or factors. The breaker is also adapted, in some ofits improved features, to be used with breakers of other than therelease from the handle type.

The main object of the invention is to produce an improved circuitbreaker which will be rugged in form of construction, dependable inoperation and durable with long continued use; and to accomplish this byan improved form of construction of a simple character in the form andrelationship of its parts and which permits economical manufacture andsimplicity in assembling. Another object is the provision of a form ofconstruction wherein the operating handle may be located close to thebase, thereby avoiding any undue projection thereof or its being subjectto accidental interference, and likewise permitting enclosure by ashallow casing, where enclosure of the parts is desired. Another object,where the handle is outside the casing, is to provide for the locationof the operating handle at the side of the breaker close to the basewhere it is in a protected position. lt likwise permits convenientenclosure of the breaker by permitting the removal of the outer casingwithout disturbing the operating handle. Another object is to provide animproved form of mechanism wherein the controlling force for causing theopening of the breaker may be made quite small. Another object is toprovide a simple-form of construction of breaker wherein any desirednumber of switch elements may be used and all controlled by one closingmechanism, and all released by the effect of any one of a number ofdifferent controlling coils. Other 0bjects and advantages of thisinvention will be understood from the following description andaccompanying drawings which illustrate a preferred embodiment thereof.

Fig. l is a front elevation of a three pole circuit breaker embodying myinvention provided (Cl. D-89) leased for permitting the opening of thebreaker; Fig. 7 is a side view of the main hook element; and Fig. 8 is aside view of the latch holding element.

Referring to Figs. 1 and 2, thc breaker is shown mounted on aninsulating base plate 1 which is shown secured to the back of the innerportion 2 of an enclosing casing. The breaker illustrated is of thethree pole type, one set of terminals 3 being mounted upon the lowerportion of the base plate and the other set of terminals 3a beingmounted upon the upper portion of the base plate. The inner portion ofthe enclosing casing is comparatively shallow, and the outer portion 2aof the casing is likewise comparatively shallow and is shown astelescoping over a portion of the inner casing and secured in place bywing nuts 2b which engage studs extending outwardly from the base plate.

The yieldable fixed contacts 4 of the breaker are suitably mounted uponthe base plate and provided with the usual auxiliary carbon contacts 4a.The contact arms 5 engage the yieldable contacts and have auxiliarycarbon contacts 5a at their upper ends. The contact arms are fixed to,but insulated from, a shaft 6 which is rotatably supported in twobearing brackets 7, one at each side of the breaker. These brackets arexed to the base plate and have outwardly extending portlons 'la forsupporting the contact arm shaft 6. The right hand bearing bracket hasan extension 7b to which one end of the operating spring 7c is secured,the other end of the spring being secured to an arm 7d secured to thecontact arrn shaft. This spring serves to quickly throw the breaker toopen position when released. Fixed to the contact arm shaft is anoutwardly extending arm 8 carrying a curved plate 8a marked On and "Offon its face. Evidently, the position of the curved plate 8a Will showwhether the breaker is open or closed, a small opening in the frontportion 2a of the casing permitting the Word On or Off to be exposed,according to the condition of the breaker.

A The operating handle 9 for closing the breaker, is external to thecasing and located at the right hand side thereof and is connected to ashaft 9a, which is pivotally supported by two out'- wardly extendingbearing supports 9b and 9c secured to the base plate within the casing.Fixed to the handle shaft is a crank element 9d which extends downwardlyfrom the handle shaft and when in closing position strikes against astop 9e on'the base plate, formed by an extension from the support forthe handle bearing brackets, or may be an independently mounted plate ornut to serve as a stop for the crank element. 'Ihis stop prevents thebreaker from being unduly strained by the operator when closing thebreaker, and also serves to limit the over-center position of the crankelement 9d, as hereinafter explained.

The breaker is closed by means of a hook, the operation of which iscontrolled by the handle through the crank element 9d. The closing hookis made up of two side plates 10a and 10b clamped together at theirlower ends and also pivotally connected to the crank pin 9! in the outerend of the crank element, as shown in Pigs. 1 and 5. 'I'he side platesof the closing hook are spaced apart from each other, in their upperportions, their upper ends forming a pair of hooks 10c and 10d. Fixed tothe contact arm shaft 6 is an inwardly extending crank arm 11 whichcarries a pin 11a at its inner end and extending sidewise therefrom tothe right of the arm ll. The hooks 10c and 10d are adapted to engage thepin 11a for the purpose of closing the breaker. That is, when theoperating handle 9 is turned upwardly to the dotted position indicatedin Fig. 3, it swings the crank 9d to the dotted position shown in Fig. 3and correspondingly raises the side plates 10a and 10b. so that thehooks 10c and 10d pass over the top of the pin lla of the arm l1 intheir upper position corresponding to the open position of the contactarms 5, as indicated in dotted lines in Pig. 3. Downward movement of theclosing handle will then cause the contact arms to be moved to theirclosed position, indicated in full lines in Fig. 3.

As it is desired to permit the opening of the breaker when attempted tobe closed, in case of the occurrence of an abnormal circuit condition,and also during running conditions, without disturbing the closinghandle from its closing position, the hooks 10c and 10d are shaped,where they engage the pin 11a, so as to readily pass of! the pin andrelease the contact arm shaft, so vthat the breaker may move to openposition. Thus. the shape of the engaging faces or edges of these hookswith the pin 11a form substantially plane surfaces; and were it not forauxiliary retaining means, the hooks would run off the pin or roller11a. Under such conditions, the breaker could not be closed, or heldclosed, by the hooks 10c and 10d Therefore, there is provided anauxiliary hook holding element 12. well shown in Figs. 3, 4 and 6 andseparately shown in Fig. 8. 'I'his holding latch or hook is pivotallymounted between the upper portions of the hook plates 10a and 10b on apin 12a. which pin is mounted upon and extends between the side hookplates. The holding hook has secured to it, at its upper end, adownwardly extending leaf spring 12b, for the purpose of normallyforcing the upper portion of the holding hook inwardly, so as tonormally engage the pin 11a and thereby prevent the hooks 10c and 10dfrom sliding off the pin.

The spring 12b also serves another function of engaging another latchingelement 13 to hold it in normal position. The latch 13 is pivotallymounted at its inner end upon a pin 13a, extending between the sideplates 10a and 10b. The outwardly extending portion of the latch 13 isadapted to be engaged by a tripping element upon the occurrence of anabnormal circuit condition and is raised to release the breaker, The

inner end of the latch 13 beyond the pivot 13a forms the hook forengaging and normally restraining the lower end of the latch holdingelement 12. These parts are shown in their normal closed position'inFigs. 3 and 4, where it is seen that the lower end of the holding latch12 is restrained by the inner end of the latch 13, so as to be locked tothe pin 11a, while the leaf spring 12b engages a notch in the upper edgeof the latch 13 in front of the pivot 13a, so as to tend to hold theouter end of the latch 13 down. When the holding latch is released, thespring tends to force the upper portion thereof over the pin 11a to sucha position that the lower end of latch l2 is engaged by and retained bythe inner end of the hook 13. Fig. 6 shows the relation of the latchingelements to each other at a time when the outer end of the latch 13 hasbeen raised by the tripping element, permitting the lower end of thelatch 12 to be released and unhooked from the pin 11a. This obviouslypermits the hooks 10c and 10d to pass oi! the pin 11a and thus permitthe opening of the breaker. In this releasing action, although thespring 12b tends to hold the latch 12 in position on the pin 11s, theforce tending to open the breaker tends to move the pin 11a. upwardly,so that, when the holding latch 12 is released, the pin 11a swings thelatch 12 counter-clockwiseon the pivot 12a against the action of thespring 12b. Thus the lower end of the latch 12 is thrown inwardly by theaction of the pin 11a, until this pin has passed from under the holdingelements, after which, the spring 12b tends to turn the latch 12 in aposition to again engage the pin lla during the closing operation of thebreaker. It should also be noted that when the breaker is closed thecenter line of the pin 9! is passed beyond the dead center lineextending between the axis of the handle shaft 9a and the axis of thepin 11d. T hus in the closed position of the operating handle of thebreaker, the breaker is held closed by reason of the over-centerposition of the pin 9]. Obviously, when the pin 11a is re- 120 leased,the breaker handle and parts controlled thereby, remain in positioncorresponding to the closed position of the breaker, until raised by theoperator for the purpose of closing the breaker in the manner alreadyexplained.

In the breaker shown in the drawings, there are provided means forautomatically tripping the breaker upon the occurrence of over-load andalso upon the occurrence of under-voltage, two over-load controllingcoils and two undervoltage controlling coils being shown and beingadapted for connection in a three phase circuit. Each of thesecontrolling elements serves to raise the front end of the singletripping latch 13. Thus any one of the controlling elements mayautomatically cause the opening of the breaker through its effect uponthis single releasing element. For securing this result, there isprovided a single tripping element 14 in the form of a pin which extendsacross the front of the breaker and is located immediately under thefront end of the tripping latch 13. The controlling elements are relatedto this tripping pin so that upon the occurrence of any one or moreabnormal conditions, this pin would be raised to actuate the releasinglatch. The tripping pin is mounted as shown in Figs. l, 4 and 5.

It is carried by a tripping bracket 14a in the form of a metal platehaving upwardly turned side portions through which the pin passes and by'the rear leg of the magnet.

which the pin is carried. These side portions of the bracket extendrearwardly to form ears 14h which are in turn pivotally mounted upon ahinge pin 14o. 'I'his hinge pin is in turn supported by studs 14d whichare xed to the base plate. A spring 14e encircles the hinge pin` and hasone end secured thereto while the other end is brought forward andengages the upper surface of the tripping bracket which assists gravityin tending to hold it and the tripping pin in their lowest position.

The controlling magnets are all supported upon a common horizontal plate15 which in turn is supported by a pair of forwardly extending jaws l5asuitably xed to the base plate. Each of the magnets has a U-shaped ironcore with upwardly extending legs upon which the coils are mounted. Thecores are xed to and supported upon the plate 15 and the legs of eachcore lie in a vertical plane perpendicular to the base plate.

The cores 16 of the two over-load coils are particularly shown in Figs.4 and 5 with the over-load coils 16a diagrammatically indicated thereon.In Fig. 4 the over-load coil is omitted upon the rear leg of the corefor simplicity and it is immaterial, as far as the present invention isconcerned, whether both legs of the core are provided with coils, oronly one leg is so provided. The particular form of magnet will be madeas desired to suit the particular conditions. On the upper end of eachfront leg of the cores 16, is pivotally mounted an armature 17. Itsshape is indicated in Figs. 4 and 5 and is in the form of a plateextending over the front leg of the core and having downwardly extendingside portions over the front leg of the core, to which it is connectedby a pin 17a which passes through the side portions of the armature andthrough the front leg of the core. Each of these armatures has arearwardly extending portion 171) which extends over the rear,leg of theover-load magnet. When the overload current attains a predeterminedlimit, in either of the over-load magnets, its respective armature willbe attracted and cause the rear portion thereof to move downwardlytowards The front end of each over-load armature is perforated toreceive a horizontally extending pin 17o, one end of which pin is inhook formto receive one end of a spring 17d, as shown in Fig. l. Thisspring extends downwardly and is suitably secured to the plate 15. Thisspring tends to hold the front end of its over-load armature down andthus cause the rear end of the armature to be raised above the rear poleof the magnet, as shown in Fig. 4, under normal conditions. Any suitablestop or adjustable means is provided to limit the unattracted positionof the armature, in any o1 the well-known ways. A graduated scale may beplaced adjacent to the armature, said scale to indicate the current forwhich the armature is set to trip. The tripping bracket 14a which islocated above the over-load magnets, is provided with a pair ofdownwardly extending portions 14j, which respectively rest upon thefront ends of the overload armatures. determined over-load, the armatureof the respective magnet carrying the over-load will be attracted andthe front end thereof raised. This in turn causes the raising of thefront end of the tripping bracket around the hinge pin 14e and therebyraises the tripping pin 14 to It is evident that upon a pre-v trip thereleasing latch 13, to cause the opening of the breaker, as alreadydescribed.

The low voltage, or under-voltage, controlling magnets 18 are shownlocated one at each side of the base plate. Each of these magnets isprovided with a pair of plates 18a in i'rontA of the coil and suitablysecured to the core of the magnet, see Figs. l and 2.. These plates eachhave an outward extension 18h at their upper ends and carry a pinextending between them on which is pivoted the armature 18o, the rearportion extending over the poles of the magnet. The front end of thearmature has a spring 18d connected to it which extends downwardly andis fastened to a pin 18e extending between the lower ends of the plates18a. The inner portion of the armature extends under the tripping pin14, so that when it is released upon the occurrence of a predeterminedunder-voltage, it will be thrown upwardly by the action of the spring18d. and so raise the tripping pin to cause the automatic opening of thebreaker, in the manner already described. For the purpose of causing theunder-voltage armature to be pushed toward the poles of its magnet whenthe breaker is closed and to so give the magnet an opportunity to retainthe armature in place, under normal voltage conditions, the armature isprovided with a projection 18j and an inclined downwardly extendingsurface at its rear end, as shown in Fig. 2. This inclined end of thearmature is engaged by any suitable projection mounted upon the contactarm shaft 6, or controlled by the movement thereof. In Fig. 1, at theleft, is shown a plate 19 mounted upon the contact arm shaft and havingan extension 19a which is over the' armature of the left-hand voltagemagnet. The right hand voltage magnet is controlled by a similarprojection 19a which in this instance is an extension from the arm orplate 8 carrying the indicator. Referring to Fig. 2, it will be evidentthat when the breaker is open, the projections 19a will be nearer thebase plate than when the breaker is closed, and that the inner ends ofthe voltage 120 armatures will be above the retained position shown inFig. 2. Thus during the closing of the breaker, the projections 19a willmove outwardly and engage the inner surfaces of the voltage armaturesand force them in position 125 to be magnetically held if normal voltageexists, the projections 19a. in the meantime passing over and in frontof the projections 18j of the armatures to the position shown in Fig. 2.If under-voltage exists in either circuit, the arma- 130 turecorresponding thereto will not be held by its magnet; and the spring 18dwill cause it to be thrown to raise the tripping pin 14, the projection19a. having passed away from the projection 18j of the armature.

It will be understood that the automatic tripping magnets may bevariously arranged in relation to the breaker mechanism and may, ofcourse, be made to respond to any abnormal condition desired and may bevariously connccted to suit the particularrequirements. In the presentcase, as indicated in the drawings, the left hand under-voltage magnet18 is connected between the left hand terminal 3 and the middle terminalof the three phase circuit; and the right hand voltage magnet isconnected between the right hand terminal 3 and the middle terminal 3.The right hand over-load coil is connected between the right handterminal 3 and the right hand contact arm 5; and the left 150 handover-load coll is connected between the left hand terminal 3 and thel'eft hand contact arm 5, while the middle terminal 3 is connecteddirectly to the middle contact arm.

Although the particular circuit breaker described is adapted for threephase alternating current, my invention is likewise adapted for thecontrol of direct current and may be used in various types of circuitbreakers. It is also evident that it is adapted for the control of asingle pole breaker, as well as for breakers having any desired numberof poles, or switch arms, all controlled by a single closing andreleasing device and subject to automatic opening by any desired numberof control magnets operating under any desired conditions. Wherenecessary, insulating barriers may be placed between the difi'erentcontact arms and the contacts controlled therebyv for the purpose ofpreventing flashing over from one pole to the adjoining pole, but suchbarriers are omitted from the present drawings for the sake ofsimplicity and clearness.

Although' I have described a preferred embodiment of my invention, itwill be understood that the same may be embodied in various forms ofconstruction and relationship of the parts and various modificationsmade without departing from the scope thereof.

vI claim:

1. A circuit breaker comprising a base plate, a rotatable contact arm, apivotal support for said contact arm mounted on said base plate, arotatable operating shaft supported on said base plate below saidsupport, an operating handle connected with said shaft and located atone side of the breaker, an arm fixed to said shaft below said contactarm, an arm connected with said contact arm and extending inwardlytoward said base plate, and a releasable hook device connecting saidinwardly extending arm and said arm fixed to said shaft for closing saidcontact arm.

2. A circuit breaker comprising a base plate, a rotatable contact arm, apivotal support for said contact arm mounted on said base plate, arotatable operating shaft supported on said base plate below saidsupport, an operating handle connected with said shaft and located atone side of the breaker, an arm fixed to said shaft below said contactarm, an arm connected with said Contact arm and extending inwardlytoward said base plate, and a releasable hook device connecting saidinwardly extending arm and said arm fixed. to said shaft for closingsaid contact arm, said device comprising a main latch and a latch forholding the main latch.

3. A release from the handle circuit breaker comprising a base plate, acontact arm, a pivotal support on said base plate for said contact arm,a crank arm rigidly connected with said contact arm and extendinginwardly toward said base plate, a hook element releasably connectedwith said crank arm, an operating shaft below said support, a crank armon said operating shaft connected with said hook element, a holdinglatch for maintaining said hook element in operative engagement withsaid first-named crank arm, and a tripping device for releasing saidholding latch.

4. A release from the handle circuit breaker comprising a shaft, acontact member fixed to said shaft, an arm connected with said shaft, apin carried by said arm, a hook element engaging said pin, a holdinglatch pivotally supported on said hook element and engaging said pin fornormally holding said hook element in engagement with said pin, anoperating shaft having an arm connected with said hook element, andmeans for automatically tripping said holding latch.

5. A release from the handle circuit breaker comprising a shaft, acontact member fixed to said shaft, an arm connected withsaid shaft, apin carried by said arm, a hook element engaging said pin, a holdinglatch pivotally supported on said hook element and engaging said pin fornormally holding said hook element in engagementv with said pin, anoperating shaft having an arm connected with said hook element, andmeans for automatically tripping said holding latch, said last-named armpassing beyond the center line of said pin and said operating shaft inthe closed position of the breaker.

6. A circuit breaker comprising a base plate, a rotatable contact arm,an arm connected with said contact arm and extending inwardly towardsaid base plate, said arm having a pin on its inner end, a rotatableoperating shaft supported on said base plate below said contact arm, andan upwardly extending hook moved upwardly and downwardly by rotation ofsaid shaft, the upper end of said hook passing over said pin when in itsupper position to engage the same and causing the contact arm to closeby the downward movement of said hook.

7. A release from the handle circuit breaker comprising a rotatableContact element, a rotatable operating element, and a latching mechanismoperatively connecting said elements, said mechanism comprising a mainlatch for moving said contact element to closed position, a latch forholding said main latch in operative engagement for moving said contactelement, and a tripping latch for normally restraining said holdinglatch.

8. A release from the handle circuit breaker comprising a rotatablecontact element, a rotatable operating element, a latching mechanismoperatively connecting said elements, said mechanism comprising a mainlatch for moving said contact element to closed position, a latch forholding said main latch in operative engagement for moving said contactelement, a tripping latch for normally restraining said holding latch,and means for automatically moving the tripping latch.

9. A release from the handle circuit breaker comprising a rotatableshaft, a contact member mounted on said shaft, an operating shaft havinga crank arm, and a releasable hook device connecting said crank arm andsaid first named shaft, said crank arm being carried over-center in theclosed position of the breaker.

10. A release from the handle circuit breaker comprising a shaft, acontact member carried by said shaft, an arm connected with said shaft,a pin carried by said arm, a pair of hook plates engaging said pin, aholding latch for retaining said hook plates in engagement with said pinandi pivotally supported between said plates and also engaging said pin,an operating shaft having an arm connected with said hook plates, andmeans for automatically tripping said holding latch.

11. A release from the handle circuit breaker comprising a shaft, acontact member carried by said shaft, an arm connected with said shaft,a pin carried by said arm, a pair of hook plates engaging said pin, aholding latch for retaining said hook plates in engagement with said pinand pivotally supported between said plates and elso engaging said pin,an operating shaft having an arm connected with said hook plates, andmeans for automatically tripping said holding latch, said arm passingbeyond the center line of said pin and said operating shaft in theclosed position of the breaker.

12. A circuit breaker comprising a common rotatable shaft, a pluralityof movable contact members carried thereby and fixed thereto, arotatable operating shaft, a releasable latching device operativelyconnecting said operating shaft and said first named shaft for rotatingsaid rst-named shaft and thereby moving said contact members to closedposition, a tripping mechanism for releasing said latching device, asingle movable element for controlling said tripping mechanism, and aplurality of magnets for individually controlling the movement of saidsingle element.

13. A circuit breaker comprising a common rotatable shaft, a pluralityof movable contact members carried thereby and fixed thereto, arotatable operating shaft, a releasable latching Gti device operativelyconnecting said operating shaft and said first named shaft for rotatingsaid first-named shaft and thereby moving said Contact members to closedposition, a tripping mechanism for releasing said latching device, asingle movable element for controlling said tripping mechanism, aplurality of magnets for in dividually controlling the movement of saidsingle element, a main base plate for the breaker, and a common supportfor said magnets mounted on said main base.

14. A release from the handle circuit breaker comprising a rotatableshaft, a plurality of contact members carried by said shaft and fixedthereto, a rotatable operating shaft, a device connecting said shaftsfor closing the breaker by rotation of said first-named shaft, saiddevice comprising a hook, a holding element for retaining said hook inposition, a pivoted element for controlling the movement of said holdingelement, a plurality of tripping magnets, and a movable element actuatedby each of said tripping magnets for aiecting said pivoted e1- ement tocause the release of said holding element.

JOHN R.. SANBORN.

